Final answer:
The state of matter for a reactant or product in a chemical equation is indicated by symbols placed in parentheses after the formula, such as (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous solutions. Coefficients before the formulas indicate the number of molecules or units of that substance.
Step-by-step explanation:
In a chemical equation, the state of matter for a reactant or product is indicated by using symbols placed in parentheses after the formula. Common symbols include (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous solutions (substances dissolved in water).
For example, the equation 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g) represents the reaction between sodium (a solid) and water (a liquid) to produce sodium hydroxide (an aqueous solution) and hydrogen gas (a gas).
The coefficients before the formulas in a chemical equation indicate the number of molecules or units of that substance in the reaction.